If you are going purely for looks / anims ... Prolly Fem pandas, they are pretty cool.
If you care about racials / min/max DPS ... Troll=UD>Orc (IIRC, may be wrong).
The change / addition of Touch of the Grave for UD puts them in a strong position for racial consideration now.

against, for instance, a shadowplay or a shadowcleave, undead would be best. you can will the 1120 amount of fears you get, but against melee cleaves and mages, orcs are a lot better, because stuns last for less duration on you.

3rd is the goblin, if you get good at actually using the rocket jump as a life saver or as a good gap closer etc. - and they have the coolest attack animations in the game

Blood elf is shit because their silence DRs with everything, and there's no reason to roll a troll at all.

undead male is the only true rogue model. not only for the horde, no! even for the aliance theres only male ud rogues that are considered "real" rogues... sadly they cannot get them and thus all alliance rogues will forever be considered lame little sissies!